When using a glass thermometer, how long should it remain in the mouth for an accurate reading?

For an accurate reading when using a glass thermometer orally, it is important to allow sufficient time for the thermometer to equilibrate with the temperature of the body. The recommended duration of 3-10 minutes strikes a balance between ensuring that the thermometer has enough time to accurately reflect the body's temperature without being excessively long.

This time frame is essential because it allows the mercury (or alcohol in some thermometers) to stabilize and show a reading that truly represents the oral temperature. If the thermometer is not left in place for long enough, the reading may underestimate the actual body temperature, leading to potential misinterpretation of a person's health status.

Longer times, such as 5-8 minutes or 10-15 minutes, while they may also provide accurate readings, are often unnecessary and can be impractical in a clinical setting, where quicker assessments are often preferable.